In the present study, using morphologic examination, we also found that As2O3 (0.5 and 5 ppm) effectively suppressed myogeninexpression and retarded muscle regeneration in mouse soleus muscles after injury by glycerol.

We observed an increase of myogeninexpression and Akt phosphorylation in the soleus muscles on day 3 after glycerol injection, but it was suppressed in As2O3-treated mice compared with control mice (Figure 8).

The present study suggests an alternative mechanism based on ERK activation: when the C26 hosts are treated with PD, and ERK is thus inhibited, Pax7 and myogeninexpression is restored to control values.

It has been hypothesized that creatine increases the expression of myogenic transcription factors such as myogenin and myogenic regulatory factor-4, which increases muscle mass and strength.119 Creatine supplementation increases muscle phosphocreatine levels leading to a decrease in muscle relaxation time.120,121 This may increase the ability to perform high-intensity exercise as well as enhance muscle protein synthesis, lean skeletal muscle mass, and strength during periods of high intensity training.

The differences in the expression of myogenic regulatory factors, MyoD and myogenin, as well as GATA4 and MEF-2, in response of P19 cells to OT and OT-GKR stimulation, can influence the developmental decisions of stem cells differentiating into the skeletal or cardiac muscle lineage.

The beneficial effects of exercise may, at least partly, be brought about by an increase in the expression of myogenin (Siu, Donley et al 2004), a reduction of the occurrence of apoptosis (Siu, Bryner et al 2004), and suppression of the muscle specific ubiquitin ligase atrogin (Leger et al 2006).